Structural beams such as I-beams and hollow structural section (HSS) beams and columns have been fabricated by welding together various components forming the beam. In one fabrication process, flat steel plates are positioned and welded into a desired beam shape. The beams may be fabricated in a plurality of steps, including securing the flat steel plates in assembly fixtures or welding jigs to hold the components in a desired position, then tack welding the flat steel plates to fix the components in the desired shape. In a subsequent step, the flat steel plates are structurally welded to complete the beam. The structural welding may be performed removed from the welding jigs to enable the welding jigs to be used for production of another beam.
Automated welding and robotics have been utilized within steel fabrication systems to increase production and/or to reduce human exposure to harsh and/or undesirable working conditions. Such systems may include an automated carriage that moves a welder along components to be joined, which are positioned in the welding jig. In yet another alternative, a welding system may include a welding robot that moves a welder into desired positions for welding. In the case of beam fabrication, an operator may tack weld the components positioned in the assembly fixtures or welding jigs in the desired beam shape. Alternatively, a robot may be used to tack weld the beam components using a hand-operated welder to join the plates in the desired beam shape. Subsequently, the tack-welded beam may be removed to a structural weld station, where the components are structurally welded to complete the beam. The structural weld station may be an automated weld station including an arc welder positioned on a movable carriage to complete the structural welds. In the automated weld station, the welder may be positioned in desired location relative to the workpiece, and the welder welds the workpieces as the automated carriage moves along a desired path.
In view of the foregoing problems and shortcomings of existing steel fabrication systems, the present application describes a method and apparatus to overcome these shortcomings.